Technical Field
The present disclosure relates to a screening apparatus and a screening method for illuminating microparticle, such as cells, detecting a microparticle to be a target sample based on fluorescence emitted from the microparticle, and selectively sucking and collecting the relevant microparticle.
Background
In the related art, microparticle screening apparatuses are widely used as apparatuses for identifying and sorting microscopic samples, such as cells, in research and testing in the medical field. Recently, in research and testing organizations, there is a need for obtaining identifying and sorting processes of the samples without fracture and for increasing efficiency of research and testing by performing those processes more accurately. Particularly, in a certain field, due to an increasing need for performing the identifying and sorting on a cell-by-cell basis, there is also a need for increasing accuracy and efficiency in the identifying and sorting processes on a cell-by-cell basis.
FIGS. 26A and 26B are diagrams for explaining an operation of a screening apparatus of the related art. FIGS. 26A and 26B show an example in which all microparticles, including a microparticle M (target sample) emitting fluorescence of a maximum luminance, are sucked from a well 501 in a measurement plate 500 and collected into a well 508 of a receiving plate 507.
In the screening apparatus of FIG. 26A, when a suction pump 504 operates in response to a command from a control unit 503, a suction-ejection capillary 505 sucks all microparticles MS, including a microparticle M emitting fluorescence of a maximum luminance, from a well 501, selectively and being distinguished from microparticles in another well 501. Thereafter, the suction-ejection capillary 505 ascends in a Z1-direction and descends in a Z2-direction to place a distal end portion 506 of the suction-ejection capillary 505 into a liquid A′ in the well 508 of the receiving plate 507 and to discharge all the microparticles MS into the well 508 (FIG. 26B). In other words, all the microparticle MS can be collected from the well 501 of the measurement plate 500 with a movement operation of the measurement plate 500 in X- and Y-directions and a vertical movement operation of the suction-ejection capillary 505 in a Z-direction by a collecting section. As a result, the microparticle M which is a target sample can be detected from among a large number of microparticles and selectively collected (Japanese Laid-Open Patent Publication No. 2008-249679).
The aforementioned configuration of the related art has disadvantages described below. In a case where a large number of wells are arranged on a measurement plate, it is possible to prevent malfunctioning such as suction of a sample from a well other than the well containing a target sample. However, it merely selectively sucks all microparticles in a well containing a microparticle satisfying collecting conditions as suction target objects, and it is extremely difficult to accurately suck and collect a target sample on a cell-by-cell basis.
Further, with a shape of a distal end portion of the suction-ejection capillary and a shape of the well, or a positional relationship between them as shown in FIGS. 26A and 26B, there is a possibility that, during a suction operation, a single cell which is a target sample cannot be sucked accurately due to an influence of fluid resistance produced in the liquid in the well.